Gemini 105mc conversion Diesel to EV?

[Semloh]

search for his Facebook page with lots of info about his system

alvejakten

[captlloyd]

Originally Posted by StuM

"power cruising"? What sort of range do you want? How are you going to recharge your batteries? Battery bank size and energy sources are the major constraints with EP. You need to clarify your use case.

Exactly and with a 105 you would probably being doing a fair share of motor sailing too.

[skipmac]

Hi Storx,

Sorry if I missed this point but can you post the source for your 50kW bike motor and controller?


Thanks

[dperchlik]

Remember that 20kW at 48v is over 400amps!
You will never get 20kW if your system and internal battery resistance is more than a few milli ohms. 1mOhm x 400amps = 0.4V and I2R = 160watts.

[Cadence]

If the engine is bad how is the rest of the boat as it pertains to sailing?
I could be wrong but believe the drive was through a leg. I've read have problems hence the OBs.
FYI

[zstine]

just thinking outloud....

50kW = 67Hp way more than you need. The OEM motor is 27Hp per sailboatdata.com and owner says 50% throttle @ cruise... 20kW max motor (=27Hp) seems big enough. EVwest 27Hp moto model AC-9 is $2,625

EVwest model S battery spec 5.3kWh, 22.8V, $1580 each (4x 21.2kWh & $6,320)

so cruising at 50% OEM HP ( = 10kW draw) you will only be able to run 2 hours before you kill 4 model S batteries! that's about a 10 mile range, which is fine if you are willing to wait for wind to go any significant distance.

Charging is a big issue too. What's the point of running EV if you need a generator to charge the batteries. Are you going to be a dock queen and recharge via shore power? If not, you need a lot of solar. assuming you can get rated output for 5 hours (eg. tropics), you need 4000 watts of panels, or about 14 of the big 60 cell roof panels. That's certainly more real estate than you have... and again, that's for a 10mile range.


Cost of panels ~$1/watt or $4,000 plus mounting, charge controller, wiring... maybe $6-$8k if you DIY. plus the above batts and motor add ~$9k. So you are looking at least $15,000 probably closer to $20k all said and done.

[KP44]

I was talking to another sailor in the yard yesterday about an electric boat. The sailor says it has a huge solar array and seems to be OK. I don't remember where he said it is. There are others. But I don't know of any ocean cruisers except experimental vessels that have (almost) unlimited funding and support.

If given the opportunity, I would have repowered with a motor instead of an engine. The extra weight could be made up with batteries, and maybe a diesel gen-set.
If the technology has improved, it's probably the way to go.

[harlem24]

As I said, look at the Sailing Uma website.
For them it seems to work. They been in all of the caribean, up the east coast and just crossed the Atlantic to England.
They have two solar panels and about 14kWh of LiFePo4 batteries.
Not sure if they have working regen.

[harlem24]

Originally Posted by KP44

I was talking to another sailor in the yard yesterday about an electric boat. The sailor says it has a huge solar array and seems to be OK. I don't remember where he said it is. There are others. But I don't know of any ocean cruisers except experimental vessels that have (almost) unlimited funding and support.

If given the opportunity, I would have repowered with a motor instead of an engine. The extra weight could be made up with batteries, and maybe a diesel gen-set.
If the technology has improved, it's probably the way to go.

Sailing Uma and Rigging doctor both crossed the Atlantic and both are non-professional sailor with electric engines and very limited funding...

[warrior 90]

Here are my 2 cents

First of all
The Westerbeke engine is a marine conversion of the Mitsubishi L3E engine. This engine was used in tractors, construction machines and what not ?? all over the place and replacement engines to spares are easy to find and dirt cheap. This is a very good engine if maintained properly and fuel consumption is close to nothing. The two 18 gallon fuel tanks will give You a very nice range for Coastel, ICW and Caribbeans.

THE EV ROUTE
Following is the web site from Sillete, the manufacturer of the Sonic Type 2 drive that is installed on the Gemini together with the 27 Hp Westerbeke engine.
https://www.sillette.co.uk/sonic_typ...ran_drive.html

Watch the rated HP ratings = Torque Loads !!!
A 50 Kw motor has way too much torque and even with 25 KW you are getting close to the upper limits.
As You can see they also have an electric sail drive version but it´s a little different then the outdrive version. However the parameters as far as motor sizing, torque loads, reductions and prop size to match with the Sonic drive are similar.
https://www.sillette.co.uk/sonic_ele...saildrive.html
They are working with Lynchmotors in the UK and they use a very cheap and high efficient DC pancake motor. Even so the motor has not a high IP insulation rating in case of the Gemini 105 with a totally dry engine compartment this will not be a problem. This lower IP rating on the flip side will give You a much better heat dissipation/cooling, which is Your mayor concern for electro motor efficiency. It is also a brushed motor but here are YT videos to give You an idea what You are up to in case of trouble shooting and repair......
In any case.... since these motors are so cheap and easy to repair and replace. I would always keep a complete spare motor on board.....
The Lynch Motor
A very unique design with a lot of history in racing and DIY and definitely a legend

https://www.youtube.com/watch?v=rmdamS2bjYc

https://www.youtube.com/watch?v=U13r_tkHxuY

What You also definitely wanna evaluate on a Gemini is the weight of the motor, weight of the total installation and weight distribution. The Westerbeke with the transmission according to spec sheet is 274 Lbs + 36 gal of fuel

So here is the Lynch motor Mod. LEM 200 up to 15 KW.....
https://lynchmotors.co.uk/pdfs/lmc-lem-200.pdf
As You can see the best efficiency rate is around 4100 RPM. That is way higher then the Westerbeke shaft power curve. So with the proper reduction You should have no problem to match the Sonic drive to Your desired spes even without changing the prop which is a lot cheaper. Here is a close up photo on the bottom that shows the easy principles of designing Your own motor mount set up with the proper gear.
https://lynchmotors.co.uk/marine_mar...ive-boats.html
and also here

https://www.youtube.com/watch?v=uwa1M85q8Ao

Here are some suppliers for the " TIMING PULLEYS & BELTS " which is a lot more flexible and simpler power tran then using gears > easy change, no lube, no maintenance, cheap .......
https://www.motionindustries.com/tax...leys/browse/en
You can also check on Amazon...
https://www.amazon.com/Boston-Gear-D.../dp/B006R9AH5Q

However depending on where and how You wanna use the boat. You can also go to a higher KW motor.
Here is the Mod. LEM 2x2.....
https://lynchmotors.co.uk/pdfs/lmc-lem-2x2.pdf

This is the same motor but with two identical motors mounted on the same shaft.
This will give You two motors in one for added safety when one motor fails but the mounting to the Sonic Drive will be still as simple as with only one motor.
Of course now You also have double power but with less heat.

If You should decide to go with Lithium here are my preferd sources for reasons of price
Winston Battery, CALB, LiFePO4 Battery - Evlithium
https://www.ev-power.eu/Winston-12V-sets/
I like the BMS 123 Smart from EV-Power for it´s simplicity. Also has Bluetooth
https://www.ev-power.eu/Battery-Mana...tooth-4-0.html

Carefully watch the details on this YT channel and form Your own opinion
https://www.youtube.com/channel/UCRq...QdaU_ePXfMD9xA

He did an of the shelf conversion with those motors many years ago and now upgraded to 72 Volts with a new controller with way much better results.
As You might realize he built this system by himself. Now go to all them beautiful YT channels here mentioned and ask Yourself. What are You going to do if there is a problem. Can You fix it Yourself ? Where do I get the spare parts. What tools do I need on board ? What will Your situation look like if You can´t fix it Yourself ?

!!! Further considerations...... there is different legislation "DEPENDING ON COUNTRY ".... in ref to boat safety ,insurance cover etc. for EV installations on boats for up to 48 Volts and over 48 Volts.
In regards You should also pay VERY SPECIAL ATTENTION to the facts that standard in the Gemini the propane gas bottle sits right next and all open to the engine compartment and standard the fridge also is 110 V /propane with a constant open flame.

Of course there is also the less spectacular but very valid conversion to an electric outboard engine as You mentioned.

And of course there is always the big question. How will You charge the batteries ???

On the Gemini there is comfortable space for ca. 400 w of latest solar tech + maybe some additional panels on the life lines. That´s barely enough for consumers on board. I don´t see space for a lot more green dreams without the help of some dino fuel on board.

So things are adding up. If You wanna start a YT channel I am sure there will be a lot of attention. However if You wanna get on the water and go sailing I am sure the Mitsubishi lawnmower engine might be worth while thinking.

Further more ..... make a VERY VERY deep inspection of the Sonic Drive. There are issues with the reverse release and other little tricky tid bits. Sillette has a good customer Service but spare parts for the Sonic Drive are unique and expensive. I also heard some unconfirmed rumors that Sillette will stop to manufacture the Sonic Drive.

Good Luck and Cheers

[Scaramanga F25]

At way below hull speed on catamarans with modern electric propulsion, you are lucky to ger 3 hours of operation and these have 8 solar panels and more than 8 batteries. Their weight is much more than a diesel engine.
It will not get off in a grounding. Fix the diesel or use an outboard(s).
Big mistake. Experience.

[mikedefieslife]

Originally Posted by harlem24

As I said, look at the Sailing Uma website.
For them it seems to work. They been in all of the caribean, up the east coast and just crossed the Atlantic to England.
They have two solar panels and about 14kWh of LiFePo4 batteries.
Not sure if they have working regen.

I'm not sure it does. Well maybe now but originally, it seemed a very poor system. slow and extremely limited range saw them struggling a lot, and having to spend hours tacking up estuaries and the like. They talked about how light the motor was, and ignored the fact the lead acid batteries they put in at the time weighed more than the engine and fuel combined.

I've not really seem them use since the sponsored switch to an LFP bank. That is has possibly made it more practical.

In answer to the OP's question, there are undoubtably some Gemini's that converted to EV, years ago I saw a YT video on one running a LFP bank. Again it was limited.

Personally, I would love an electric motor as auxiliary power. On a cat it would be possible to have both. Outboard or dropdown pod mounted electric motors and an outboard as a backup

[johnny AoB]

You already have 26 replys so this is a hot topic. Besides the links above take a look at: https://www.adventuresonboats.com/ma...ic-motors.html There are close to a hundred links on EV.
Good luck and have fun or it ain't worth doing.

[Mr B]

The Sonic drive has now stopped production,
They still have spares for it, But not sure how long they will last,

My Westy 30B uses 3/4 US gallons per hour,
Its a Mitsibishi engine, Buy one from a Mitsubishi dealer ( Tractor dealer) and put your existing heat exchanger on it,

Heat exchanger replaces Radiator, = Marinised,

[Brewgyver]

Originally Posted by harlem24

Sailing Uma and Rigging doctor both crossed the Atlantic and both are non-professional sailor with electric engines and very limited funding...

If you actually watch all of Rigging Doctor's videos, you'll see that they spent MANY MANY days drifting on their Atlantic crossing. Once into the doldrums, they're basically flotsam.

They spent a significant amount of time running a Honda generator attempting to recharge their bank to make some headway...